Somvati Amavas, or Somavati Amavasi, is the no moon day that falls on a Monday, or Somwar, in a traditional Hindu lunar calendar. It is a rare occurrence in a year and it is considered highly auspicious by devout Hindus in North India. Taking a holy dip in River Ganga is considered to help in attaining Moksha. Somvar (Monday) is dedicated to Lord Shiva and the Amavasi falling on the day makes it even more auspicious.

The significance of Somvati Amavas was narrated to Yudhishtira, the eldest of the Pandavas by Pitamaha Bhisma in the Mahabharat. It is widely believed that people who perform a holy bath in the holy rivers on the day would be prosperous, free of diseases and would be free from grief and sorrow. On the day thousands of devotees take a holy dip in River Ganga at Haridwar, Triveni (Prayag) and other places.

Amavas day is considered auspicious for performing Tarpan and Shradh rituals dedicated to dead ancestors. It is believed that by taking a holy bath on Somvati Amavas in the holy rivers the soul of ancestors will rest in peace.

Married women perform ritualistic bath in holy rivers on Somvati Amavasi for a happy family life and for the long life of husbands. In some regions, women also worship the pipal tree on the day.

Somavara Amavasi Vrat is observed for a long and happy married life by couples.

Many devout Hindus also fast on the day and some people only have a single meal.